Differential hippocampal gene expression is associated with climate-related natural variation in memory and the hippocampus in food-caching chickadees.

There is significant and often heritable variation in cognition and its underlying neural mechanisms, yet specific genetic contributions to such variation are not well characterized. Black-capped chickadees present a good model to investigate the genetic basis of cognition because they exhibit tremendous climate-related variation in memory, hippocampal morphology and neurogenesis rates throughout the North American continent, and these cognitive traits appear to have a heritable basis. We examined the hippocampal transcriptome profiles of laboratory-reared chickadees from the two most divergent populations to test whether differential gene expression in the hippocampus is associated with population differences in spatial memory, hippocampal morphology and adult hippocampal neurogenesis rates. Using high-resolution mRNA sequencing coupled to a de novo transcriptome assembly, we generated 23 295 consensus sequences, which predicted 16 206 protein sequences with 13 982 showing high similarity to known protein sequences or conserved hypothetical proteins in other species. Of these, we identified differential expression in nearly 380 genes, with 47 genes specifically linked to neurogenesis, apoptosis, synaptic function, and learning and memory processes. Many of the other differentially expressed genes, however, may be associated with other functions. Our study presents the first avian hippocampal transcriptome, and it is the first study identifying differential gene expression associated with natural variation in cognition and the hippocampus. Our results provide additional support to the hypothesis that population differences in memory, hippocampal morphology and neurogenesis in chickadees have likely resulted from natural selection that appears to act on memory and its underlying neural mechanisms.

Population genetic structure and its implications for adaptive variation in memory and the hippocampus on a continental scale in food-caching black-capped chickadees.

Food-caching birds rely on stored food to survive the winter, and spatial memory has been shown to be critical in successful cache recovery. Both spatial memory and the hippocampus, an area of the brain involved in spatial memory, exhibit significant geographic variation linked to climate-based environmental harshness and the potential reliance on food caches for survival. Such geographic variation has been suggested to have a heritable basis associated with differential selection. Here, we ask whether population genetic differentiation and potential isolation among multiple populations of food-caching black-capped chickadees is associated with differences in memory and hippocampal morphology by exploring population genetic structure within and among groups of populations that are divergent to different degrees in hippocampal morphology. Using mitochondrial DNA and 583 AFLP loci, we found that population divergence in hippocampal morphology is not significantly associated with neutral genetic divergence or geographic distance, but instead is significantly associated with differences in winter climate. These results are consistent with variation in a history of natural selection on memory and hippocampal morphology that creates and maintains differences in these traits regardless of population genetic structure and likely associated gene flow.

Spatial memory: are lizards really deficient?

In many animals, behaviours such as territoriality, mate guarding, navigation and food acquisition rely heavily on spatial memory abilities; this has been demonstrated in diverse taxa, from invertebrates to mammals. However, spatial memory ability in squamate reptiles has been seen as possible, at best, or non-existent, at worst. Of the few previous studies testing for spatial memory in squamates, some have found no evidence of spatial memory while two studies have found evidence of spatial memory in snakes, but have been criticized based on methodological issues. We used the Barnes maze, a common paradigm to test spatial memory abilities in mammals, to test for spatial memory abilities in the side-blotched lizard (Uta stansburiana). We found the existence of spatial memory in this species using this spatial task. Thus, our study supports the existence of spatial memory in this squamate reptile species and seeks to parsimoniously align this species with the diverse taxa that demonstrate spatial memory ability.

Rosai-Dorfman disease mimicking parasagittal meningioma: case presentation and review of literature.

BACKGROUND: Sinus histiocytosis with massive lymphadenopathy was originally described by Rosai and Dorfman in 1969. It usually presents with bilateral painless cervical lymphadenopathy. In extremely rare circumstances, the CNS can be affected. Only 21 prior cases of intracranial involvement have been reported. CASE REPORT: A 33-year-old white male presented with a 2-week history of progressive cephalgia. The patient underwent MRI testing that revealed an enhancing mass in the right parasagittal region with associated edema. Preoperative diagnosis was right parasagittal meningioma. The patient underwent craniotomy with complete resection of the mass. Histopathology was compatible with Rosai-Dorfman disease (RDD). CONCLUSION: Rosai-Dorfman disease is rarely found intracranially; however, its ability to mimic meningioma as well as other pathologies underlines its importance. With so few reported cases of intracranial involvement, more experience will be necessary before this clinical presentation and prognosis can be clearly outlined.

Complex vertebral arteriovenous fistula and ruptured aneurysm in neurofibromatosis: a therapeutically challenging case.

The objective and importance of this study was to describe the challenges encountered with treating a high-flow vertebral arteriovenous fistula (AVF) and ruptured aneurysm in a patient with life-threatening hemorrhage. A 36-year-old female with Neurofibromatosis type 1 (NF1) presented 2 weeks after uneventful cesarean section with a rapidly expanding pulsatile neck mass. Angiography demonstrated a complex left vertebral AVF and multiple associated vertebral artery aneurysms. Emergent endovascular coil embolization was performed using a retrograde and antegrade approach to occlude the fistulas and trap the ruptured aneurysm, successfully treating the acute hemorrhage. Subsequent definitive therapy was accomplished utilizing a combined neurointerventional and neurosurgical strategy of direct-puncture acrylic embolization and ligation of the vertebral artery. Recent advances in neurointerventional technology allow novel approaches in the primary and/or preoperative treatment of complex vascular lesions such as those seen in NF1.

Evolving experience with direct puncture therapeutic embolization for adjunctive and palliative management of head and neck hypervascular neoplasms.

OBJECTIVES: The use of percutaneous, direct puncture therapeutic embolization (DPTE) of hypervascular head and neck neoplasms is a relatively new modality that may be used to supplement or supplant conventional endovascular transarterial embolization. Although the preliminary clinical experience reported by a single group has been favorable, extensive case series experience is lacking. This prompted us to review our recent clinical experience with these techniques to determine safety, efficacy, and emerging role in the overall neurointerventional therapeutic armamentarium. STUDY DESIGN: A retrospective analysis of the previous 34 consecutive cases of hypervascular tumors undergoing DPTE referred to our service for therapeutic devascularization was performed. METHODS: Complete case record review was undertaken. Twenty-six of 34 cases involved DPTE of head and neck neoplasms. Conventional diagnostic angiography was performed for therapeutic planning and to assist in precise localization. When performed, standard microcatheter transarterial embolization techniques were used either before or after attempted DPTE. Cyanoacrylate embolic mixtures (n-butyl cyanoacrylate [NBCA], lipiodol, powdered tungsten) were used in 21 of 24 cases, and absolute ethanol in 3 of 24. Direct puncture angiography of the targeted tumor neovasculature was always performed before DPTE. RESULTS: Twenty-four of 26 cases had technically successful DPTE. Combined transarterial embolization with DPTE was used in 16 of 24 cases, although for the last 12 cases, 9 were treated predominantly or exclusively by DPTE. There were no major or minor clinical complications, and there was one asymptomatic technical complication. Total or near-total devascularization was achieved in all cases. All preoperative cases had excellent hemostasis within the resected tumor bed. CONCLUSIONS: Our results lend further support to the safety and efficacy of DPTE in the management of hypervascular neoplasms of the head and neck. With our increasing experience, this technique is evolving into a primary therapeutic modality for optimal tumor devascularization.

Recurrent carotid blowout syndrome: diagnostic and therapeutic challenges in a newly recognized subgroup of patients.

BACKGROUND AND PURPOSE: To our knowledge, recurrent carotid blowout syndrome (rCBS) has not been well described. Our purpose was to review our institution's recent experience with patients who presented with multiple episodes of carotid blowout syndrome (CBS), and who were referred for emergent diagnostic angiography and endovascular therapy. METHODS: We retrospectively reviewed the last 46 consecutive patients who had a clinical diagnosis of CBS. All patients were examined and treated prospectively according to a standardized protocol. Most patients (43 of 46) had undergone extensive primary and salvage radical surgery with intraoperative brachytherapy or external beam radiation or both. The remaining three patients had either traumatic or iatrogenic CBS. RESULTS: Twelve patients (26%) in our series had more than one episode of CBS in which a total of 32 (20 recurrent) events were observed (average 2.7, range 2-4). Intervals of rCBS ranged from 1 day to 6 years. Thirteen (65%) of 20 recurrent events were attributed to progressive disease (PD), and seven (35%) of 20 to treatment failures (TFs). In the PD group, seven (54%) of 13 had recurrent ipsilateral disease, and six (46%) of 13 had recurrent contralateral disease. Etiologies of rCBS were as follows: seven exposed carotids; seven carotid pseudoaneurysms; eight small-branch pseudoaneurysms; five tumor hemorrhages; three hyperemic/ulcerated wounds; and one aortic arch rupture. Twenty-seven of 32 events were treated with endovascular therapy, which included the following: nine carotid occlusions; 11 small-branch embolizations; three transarterial tumor embolizations; one carotid stent; and two direct-puncture embolizations. Four of six TFs were retreated successfully with endovascular therapy; the remaining two TFs were managed successfully by surgery. In the PD group, hemorrhagic complications of rCBS were managed successfully in all but one patient, who died. No permanent neurologic or ophthalmologic complications occurred. CONCLUSION: Recurrent CBS is a frequently encountered problem in which most cases are caused by PD resulting from both multifocal iatrogenic arteriopathy and occasional wound complications that are characteristic of aggressively managed head and neck surgical patients. Initial TFs are encountered often as well. Despite the diagnostic and therapeutic challenges of rCBS, most cases can be retreated effectively.

Abnormal diffusion-weighted MRI in medulloblastoma: does it reflect small cell histology?

A 12-year-old boy presented with the classic CT and MRI findings of medulloblastoma and the unusual finding of increased signal on diffusion MRI. The small-cell histology of medulloblastoma may account for the increased signal seen on diffusion MRI. Diffusion MRI with echoplanar technique may be useful in evaluation of these tumors and metastatic disease.

Pigmented villonodular synovitis of the temporomandibular joint: diagnostic imaging and endovascular therapeutic embolization of a rare head and neck tumor.

We report a case of pigmented villonodular synovitis involving the temporomandibular joint that presented as a rapidly growing tumor with extension through the skull base into the middle cranial fossa. The case is of interest not only because of the unusual extensive infiltration of this tumor but also because of the role modern diagnostic imaging and endovascular therapeutic techniques played in its diagnosis and management.

Effect of internal maxillary arterial occlusion on nasal blood flow in swine.

OBJECTIVES: The precise effects of therapeutic occlusion of the internal maxillary artery (IMA) on distal nasal mucosal perfusion are unknown. A better understanding of these effects has important implications regarding the rationale and expected efficacy of certain therapeutic interventions for epistaxis management. The authors developed an animal model to assess these issues. STUDY DESIGN: The effects of "proximal" and progressively more "distal" occlusions of the IMA on nasal mucosal blood flow (NBF) were assessed in anesthetized swine using continuous laser Doppler flowmetry. The levels of arterial occlusion were selected to simulate clinical therapeutic occlusions used for the management of epistaxis. METHODS: Nineteen swine were entered into one of four experimental groupings: proximal IMA occlusion using platinum micro-coils (n = 6), mid-grade distal IMA occlusion with polyvinyl alcohol particulate (PVA) suspensions (300 to 500 microns, n = 5), high-grade distal IMA occlusion with polyvinyl alcohol particulate suspensions (50 to 150 microns, n = 5), and sham control (n = 2). RESULTS: All embolizations resulted in acute decreases in average NBF from 120 mL/min per 100 g to 40 mL/min per 100 g (P < .05 for all groups). NBF returned to baseline in all three treated groups within 2 to 8 days after therapeutic embolization, depending on the level of occlusion (coils, 2 d; mid-grade PVA, 2-3 d; high-grade PVA, 8 d). Follow-up angiography showed recanalization and collateralization as possible methods of reestablishing NBF. CONCLUSIONS: This study supports the rationale for performing distal IMA occlusion with transarterial particulate embolization, in order to provide a longer period of time of diminished NBF. This theoretically should promote hemostasis within an injured portion of the nasal mucosa by decreasing perfusion pressure within the capillary bed. However, the benefits of distal IMA embolization must be balanced against potential ischemic complications, as may be more commonly seen with high-grade particulate embolization.

Percutaneous direct-puncture acrylic embolization of a pseudoaneurysm after failed carotid stenting for the treatment of acute carotid blowout.

We report a difficult case of recurrent carotid blowout syndrome in a patient who had a rupture of the common carotid artery with formation of a large pseudoaneurysm. Conventional management of this emergency, consisting of composite occlusion of the internal and common carotid arteries, was not possible owing to prior clinical failure of balloon test occlusion. This led to an initial attempt to cover the site of rupture with overlapping self-expanding stents, which was only temporarily successful in controlling the hemorrhage. When a subsequent episode of carotid rupture with life-threatening hemorrhage occurred, percutaneous direct-puncture acrylic embolization with temporary flow arrest was used to successfully obliterate the pseudoaneurysm.

Endovascular coil embolisation of metachronous mycotic aneurysms. Case presentation and review of technical and management issues.

SUMMARY: While receiving optimal antibiotic therapy for subacute bacterial endocarditis (SBE), a teenage girl with mild congenital mitral insufficiency presented with two separate episodes of subarachnoid haemorrhage from two rapidly evolving metachronous mycotic aneurysms within the vertebrobasilar circulation. Both aneurysms were successfully treated by endovascular coil embolisation with the GDC system. This permitted at the minimum, successful amelioration of the short term risk of rerupture of the aneurysms, and facilitated operative management of the patient's infected mitral valve. The case further illustrates the utility and effectiveness of endovascular therapy for managing not only the neurovascular sequelae of SBE, but also perhaps the enhanced ability to optimally manage the source of mycotic aneurysms. In addition, the potential limitations and risks of this therapeutic strategy are assessed.

True malignant mixed tumor (carcinosarcoma) of tonsillar minor salivary gland origin: diagnostic imaging and endovascular therapeutic embolization.

We report a case of carcinosarcoma of the minor salivary glands of the left palatine tonsil, an especially rare location. Imaging characteristics assessed at CT, MR imaging, and angiography are presented. In addition, we describe our experience with preoperative therapeutic endovascular embolization of this hypervascular tumor.

Occult spontaneous lateral temporal meningoencephalocele: MR findings of a rare developmental anomaly.

We describe a case of an occult lateral temporal meningoencephalocele discovered in a 14-year-old boy during a work-up for minor head trauma. This spontaneous encephalocele resulted from a closure defect at the former sphenoidal fontanelle. Preoperative MR images are presented.

Large haemangiopericytoma of the posterior cervical space. The role of imaging and therapeutic embolisation in the management of an unsuspected hypervascular head and neck neoplasm.

SUMMARY: We report a case of a 39-year old woman who upon developing a rapidly enlarging posterior cervical space tumour, underwent incisional biopsy prior to diagnostic imaging that resulted in nearly catastrophic haemorrhage. Subsequently, MR imaging showed evidence of marked hypervascularity, prompting diagnostic angiography and endovascular microembolization prior to surgical resection. The tumour turned out to be a large haemangiopericytoma arising from the paravertebral musculature. The case is instructive by highlighting the need for considering rare locations of hypervascular tumours in the head and neck region before attempting biopsy, which can be predicted by cross-sectional imaging studies, and the benefits of pre-operative devascularization with modern superselective microembolisation techniques.

Orbital infections.

Orbital infections account for the majority of primary intraorbital disease processes. Sinusitis is the most common etiology. Five stages of cellulitis secondary to sinusitis have been described. Systemic conditions which predispose to orbital infection include diabetes, septicemia, malignancy, and immunosuppresion. Clinical signs and symptoms include superficial inflammatory changes, as well as proptosis, limitation of extraocular motility, and visual loss. Causative agents are most commonly bacteria, with fungus, viruses, and parasites seen less frequently. Imaging is performed by CT and/or MRI which are complementary in certain cases. Differential diagnosis of imaging abnormalities includes inflammatory and granulomatous diseases, as well as neoplasm.